| 摘要 |
PURPOSE:To attain the automatic focus control and to simplify the circuit constitution by providing a lens shift mechanism to a lens system and picking up a test pattern of a prescribed black/white striped pattern. CONSTITUTION:A test pattern containing black and white stripes formed alternately with the prescribed width is provided to a test pattern film 1. The pictures on the film 1 are projected to a photoelectric transducer 3 through a lens system 2 and undergo the photoelectric conversion by the transducer 3. These picture signals are amplified by an amplifier 4 then binary coded by the 1st-3rd binary coding circuits 5, 8 and 9 and with the threshold values of the 1st-3rd level controllers 6, 10 and 11. The white and black histograms which are binary coded by the circuits 8 and 9 are counted by the 1st and 2nd histogram registers 12 and 13 and latched. The outputs of registers 12 and 13 are applied to a processing circuit 15 to perform the prescribed operation. The result of this operation is applied to a servo register 16, and a servo motor 18 is controlled by the output of the register 16. Then a lens shift mechanism 19 of the system 2 is shifted. Thus the automatic focus control is attained with a simple constitution. |
